This invention relates to gauge parts for tufting machines, and has more particular reference to looper/clip combinations for use in the selective formation of cut or loop pile.
It is known in the art to use a hook or looper having a spring clip mounted thereon. A part of the clip bears on the bill of the hook or looper adjacent the free end thereof in the production of tufted fabrics having both cut and loop pile. The loop of yarn seized by the hook or looper from the reciprocating needle selectively is retained on the looper by the clip during subsequent reciprocation of the needle and moves rearwardly of the looper bill eventually to be cut by an oscillating knife cooperable therewith to form cut pile or is released from the looper by displacement of the clip by virtue of the tension in the yarn to form loop pile, according to specific requirements.
In conventional loopers having spring clips mounted thereon the clip is formed from flat spring steel strip cut to an appropriate shape and secured to a face of the looper. Adjacent its remote end the clip is formed with a generally triangular enlargement of which the apex bears on the looper bill, and such clip is creased in register with a line of symmetry of the enlargement which passes through the apex thereof, the crease extending towards the plane of that face of the looper to which the clip is secured. The construction is illustrated in U.S. Pat. No. 3,084,645 together with its application in forming cut and loop stitches.
In our co-pending United Kingdom Patent Application No. 448-57/78 (corresponding U.S. Application Ser. No. 91,982 filed Nov. 7, 1979) there is described and illustrated a looper/clip combination wherein that part of the free portion of the clip which corresponds to the effective cutting edge of the bill of the looper is arranged in offset disposition inwardly of the plane of that face of the looper against which the free end of the clip bears in relation to the looper. In the embodiments specifically disclosed in said aforesaid co-pending Application, and in conventional looper/clip combinations such as that combination disclosed in prior United Kingdom Pat. No. 920,024, corresponding to U.S. Pat. No. 3,084,645, the clip is secured to the looper, as by screws or riveting, thus giving rise to a need to discard and to replace as a unit a particular combination in the event of damage to either of the component parts thereof.
In use, the clip is particularly vulnerable to damage, and it is usually the case in practice that damage to a particular clip results in damage to adjacent clips due to a domino effect arising from the close proximity of such adjacent clips.
Bearing in mind that the cost of the clip component is but a relatively small proportion of the total cost of a looper/clip combination, the need to discard such a combination, or indeed a plurality thereof, on account, in the first instance, of damage to or failure of a single clip represents a financial burden out of all proportion to the fault.
Even in those situations where the damaged clip can be removed from a looper and a new one secured thereto, it can only be repaired when removed from the machine and the down-time required for removing and replacing a number of the units can be out of proportion to the damage.
In the utilization of looper/clip combinations to produce cut/loop fabric, yarn tension and component precision effect the quality of the goods produced. If improper and inconsistent tension of the clips against the loopers is present, the resultant product is reflective of this difficulty. Control of these factors becomes significantly more important as the gauge of the tufting machine is reduced. When adjacent loopers are relatively widely spaced apart, manufacturing imprecision can be tolerated to a greater extent than when the gauge is fine. Moreover, the free movement of the parts and interference therebetween clearly creates difficulties when the spacing between adjacent clips and loopers is relatively close.